Bad Quality whilst exporting an animation
I also sometimes have videos smaller than full HD and when I open them in the player, the video player maximizes its window and makes the video display larger.
However, this is not a problem with Blender, but with the video player. Or maybe with the video format you choose. But if the file says it's 500 x 500 then it is all fine with the file. Maybe there is a setting in the player to play the video in original size.
What I meant by &quot;it is not stretched to 1920 x 1080&quot; is that the aspect ratio didn't change. It might be scaled to fit the height of 1080 and of course this might result in worse quality because not all software scales bitmap perfectly. But again: this is not a Blender problem. By the way, this is how it would look stretched to 1920 x 1080 and your object definitely isn't stretched like that: